President Barack Obama challenged Republicans on major tax and entitlement proposals in Tuesday's State of the Union address, unveiling sweeping new initiatives to boost the middle class while taking aim at GOP recalcitrance.

The president traveled to Capitol Hill on Tuesday for the annual speech, where he pressed Republicans to allow his proposals on issues ranging from taxes and entitlements to guns and immigration to move forward. While Obama seemed determined to advance his ambitious agenda, he must race against a window of opportunity that often closes quickly on presidents in their second terms.

Moreover, the president's plans will have to survive the brier patch of Capitol Hill, where Republicans have strenuously opposed much of Obama’s agenda and are girding for a major springtime showdown on budgets and the swift, automatic spending cuts known as the sequester.

“Let's be clear: deficit reduction alone is not an economic plan,” said Obama, who argued that his second term priorities did not represent “bigger government,” but rather, “smarter government.”

Obama spent much of the first half of his speech challenging Republicans on that central issue after two years of legislating in Washington that saw the government lurch from the brink of a shut down to the brink of a debt-limit default to the brink of automatic tax hikes.

President Barack Obama touches on the issue of gun reform during Tuesday's State of the Union address. Obama voiced the need to vote on proposed changes saying, "Gabby Giffords deserves a vote, the families of Newtown deserve a vote."

“Let’s agree, right here, right now, to keep the people’s government open, pay our bills on time, and always uphold the full faith and credit of the United States of America,” the president said.

The assertive rhetoric from Obama recalled the themes on which he successfully campaigned for re-election last fall. Tuesday’s speech mostly lived up to its billing by the White House as a coda to the liberal call-to-arms in Obama's second inaugural address on issues ranging from government spending to gay rights and immigration reform.

One issue on which Obama did not campaign -- stricter gun controls -- featured more poignantly in Tuesday's speech. Gun violence has unwittingly become a cornerstone of Obama's second term agenda following the elementary school massacre in Newtown, Conn. last December.

Gun control is an issue on which Obama faces stiffer Republican resistance, and the president took a much more personal tack in pressing lawmakers to take up his proposals. He turned victims of high-profile shootings in attendance at Tuesday’s speech in urging lawmakers to, at the very least, allow his gun proposals a vote.

"Gabby Giffords deserves a vote," he said, referring to the critically injured former Arizona congresswoman in the House chamber. "The families of Newtown deserve a vote. The families of Aurora deserve a vote. The families of Oak Creek, and Tucson, and Blacksburg, and the countless other communities ripped open by gun violence – they deserve a simple vote."

Obama’s speech on Tuesday was delivered in the same vein; the president embraced proposals that might encounter resistance in this Congress, such as new legislation to address climate change. But, in a reflection of Obama’s newfound feistiness in a second term, the president vowed to take executive action if Congress would not act.

Obama made other proposals he said would bolster the middle class. Among Obama’s proposals were: universal access to preschool for all four-year-olds, increasing the federal minimum wage to $9 an hour by the end of 2015, $50 billion in infrastructure spending, and partnerships to promote cleaner energy and improved manufacturing.

President Barack Obama explains his view on what a sequester would do to the U.S. economy while delivering the State of the Union on Tuesday.

Those initiatives, the president pledged, should not increase the deficit “by a single dime.”

To help finance those initiatives, Obama called for broad individual and corporate tax reforms, as well as savings from entitlement programs like Medicare – changes to which have been a lightning rod in recent election cycles. Those proposals carefully track with Obama's previous demands to close loopholes and deductions to raise new revenue in tax reform.

But Republicans have argued that the matter of new revenue is “settled” following a fiscal cliff deal that saw the GOP relent to higher taxes on household income above $450,000. To that end, Florida Sen. Marco Rubio, in the official Republican response, called on Obama to “abandon his obsession with raising taxes and instead work with us to achieve real growth in our economy.”

Obama’s ambitious plans come as he’s asking lawmakers to approve two other major proposals: comprehensive immigration reform that gives undocumented immigrants a pathway to citizenship, and a series of tighter controls on firearms as part of a broader effort to curb gun violence.

On immigration, the president lauded a bipartisan Senate group’s work on immigration.

“As we speak, bipartisan groups in both chambers are working diligently to draft a bill, and I applaud their efforts,” he said. “Now let’s get this done. Send me a comprehensive immigration reform bill in the next few months, and I will sign it right away."

But for as much as fiscal matters and economic policy have dominated discussion in Washington, Obama devoted a good part of his State of the Union speech to foreign policy – highlighting in particular the planned withdrawal of 34,000 American troops from Afghanistan in the next year, a tangible symbol of how that war is winding to its end.

Obama also used his speech to address some of the emergent national security issues. He condemned North Korea’s nuclear test on Tuesday and pledged to work with Congress to develop rules for the use of unmanned aerial drones in targeting terrorists for assassination. The administration has faced new scrutiny on that latter issue amid the revelation of a new White House memo arguing that the president has wide latitude to target Americans for assassination if they’re deemed to be assisting terrorist actors.

Obama additional announced a new executive order to inoculate U.S. infrastructure from a cyber-attack, by enabling greater information-sharing between the government and its partners and calling for the development of a National Infrastructure Protection Plan within 240 days.

The event, as always, was filled with Washington pomp and circumstance, including lawmakers to arrived hours earlier to reserve prime seats for themselves. Also, in keeping with tradition, outgoing Energy Secretary Steven Chu was kept spirited away from the Capitol to ensure continuity of government in case of a security incident.